MX2009001335A

MX2009001335A - Tampon insertion device for improved control and pledget placement.

Info

Publication number: MX2009001335A
Application number: MX2009001335A
Authority: MX
Inventors: Keith Edgett; Robert Jorgensen; Eugene P Dougherty Jr
Original assignee: Playtex Products Inc
Priority date: 2006-08-04
Filing date: 2007-08-03
Publication date: 2009-02-16
Also published as: CA2659887C; WO2008019095A2; US20080119778A1; JP2009545420A; EP2046257A2; KR101166956B1; JP2013126533A; KR20090034957A; RU2407497C2; EP2046257A4; CA2659887A1; US8961449B2; WO2008019095A3; RU2009104776A

Abstract

There is provided a tampon applicator assembly having a barrel with an improved fingergrip. The improved fingergrip has one or more flared portions and/or one or more rib-like or ring-like gripping structures. As a result of these features, the tampon assembly provides a user with improved control, which results in proper pledget placement and thus comfort to the user.

Description

TAMPON APPLICATOR DRAWING GRIP Field of the Invention The present disclosure generally relates to a tampon applicator assembly. More particularly, the present disclosure relates to an improved tampon applicator assembly that improves user control of the tampon applicator and bandage placement in the body. Background of the Invention A tampon applicator assembly is used to inject an absorbent or hygienic material, known as a tampon bandage, into a vaginal cavity. Commercial tampon applicator assemblies typically have a barrel and a plunger used to eject a bandage housed in the barrel. The use of such assemblies requires a user to hold the barrel and guide them easily into the vaginal cavity. This is particularly important since a portion or the entire assembly is out of a direct line of sight to the user during insertion. Accordingly, an assembly that is difficult to hold and / or control can prevent proper and comfortable application of the bandage. Another problem associated with an assembly that is difficult to hold and / or control is that the wearer frequently applies excessive restraint force on the Ref. 200013 barrel to compensate for the lack of holding capacity. This excessive force can partially deform and damage the barrel and / or plunger, thereby distorting the assembly and obstructing normal access of the bandage therefrom. As a result, the wearer may be required to apply a significant amount or excessive force to expel the bandage from the assembly, which may result in discomfort for the wearer. Thus, there is a need to provide improved tampon applicator assemblies, which improve comfortable bandage placement for the wearer. SUMMARY OF THE INVENTION The present description provides an easy-to-use tampon applicator assembly, which is easy to hold and control during insertion and removal of the applicator assembly, as well as during the expulsion of the bandage. The present disclosure also provides such a tampon applicator assembly having an improved finger grip. The present disclosure further provides such a tampon applicator assembly wherein the improved finger grip includes one or more bright portions. The present disclosure even provides such a tampon applicator assembly in which the improved finger grip includes one or more similar fastening structures to channels. The present disclosure even provides such a tampon applicator assembly in which one or more channel-like fastening structures are rings, corrugated rings, or combinations thereof. The present disclosure also provides such a tampon applicator assembly in which the improved finger grip includes one or more gradually expanded portions and one or more channel-like fastening structures. These and other advantages and benefits of the present disclosure are provided by a tampon applicator assembly having a barrel with an improved finger grip. The improved finger grip has one or more gradually expanded portions and / or one or more ring-like or ring-like holding structures. As a result of these characteristics, the tampon assembly provides a user with improved control, which results in proper bandage placement and thus comfort for the wearer. The features and advantages described above and others of the present disclosure will be appreciated and understood by those skilled in the art from the following detailed description and figures. Brief Description of the Figures Figure 1 is a side view of a tampon applicator having a finger grip gradually expanded from in accordance with the present description; Figure 2 is an exploded view of the area A in Figure 1 of the finger grip gradually expanded from the present description; Figure 3 is a side view of a tampon applicator having a gradually expanded finger grip and a plurality of clamping rings in accordance with the present disclosure; Figure 4 is a side view of a tampon applicator having a finger grip section with a plurality of corrugated ring fastening structures in accordance with the present disclosure; Figure 5 is an exploded view of the area B in Figure 4 of the finger grip section with a plurality of corrugation ring; Figure 6 illustrates two corrugated ring fastening structures oriented "in phase" in accordance with the present disclosure; Figure 7 illustrates two corrugated ring fastening structures oriented "out of phase" in accordance with the present disclosure; Figure 8 is a side cut away view of Figure 4 along line AA of the tampon applicator; Figure 8a is an exploded view of a corrugated ring fastening structure in Area C of the Figure 8; Figure 8b is an exploded view of a corrugated ring fastening structure in Area D of Figure 8; Figure 9 is an exploded side view of a tampon applicator having a plurality of corrugated ring fastening structures and additional exploded views of novel features of the corrugated ring fastening structures in accordance with the present disclosure; Figure 10 is a graphical representation of the curvature of the finger grip gradually expanded for five Ultra tampon applicators in accordance with the present disclosure; and Figure 11 is a graphical representation of the curvature of the finger grip gradually expanded for five Regular pad applicators in accordance with the present disclosure. Detailed Description of the Invention The present disclosure provides a tampon applicator assembly having a barrel with an improved finger grip. The improved finger grip has one or more gradually expanded portions and / or one or more ring-like or ring-like holding structures. As a result of these characteristics, the tampon assembly provides a user with improved control, which results in proper bandage placement and thus comfort for the wearer. Referring to Figure 1, a tampon applicator with an improved finger grip in accordance with the present disclosure is generally represented by the reference number 10. The applicator 10 includes a barrel 12 and plunger 14. The barrel 12 includes a tip 16 and a finger grip section 18. The finger grip section 18 includes the improvement of a gradually expanded portion 20. It was unexpectedly found through the consumer's test that the finger grip section 18 with gradually expanded portion 20 has a gradually expanded angle and / or optimum inclination provides improved clamping capacity, resulting in improved tampon insertion and tampon placement control. Referring to Figure 2, an exploded view of the area A in Figure 1 is provided, which details the improved finger grip section 18 with gradually expanded portion 20. The gradually expanded portion 20 has a gradually expanded angle 22, which is shape at an intersection 25 of the finger grip surface 27 and gradually expanded surface 29. The finger grip surface 27 is a virtually uniform radius surface as measured from the center line X of the barrel 12. The gradually expanded surface 29 has radii that expand uniformly, again as measured from the centerline X of the barrel 12, thereby resulting in a gradual expansion . The gradual expansion angle 20, as shown in Figure 2, was measured from the outer surfaces of the surface 27 toward the gradual expansion surface 29. In addition to the gradual expansion angle 22, it was unexpectedly found that; Gradually expanded 20 has an optimum curvature and / or inclination 24, improved holding capacity is provided. The optimum curve 24 of the gradually expanded portion 20 can be determined by measuring the change in the height increase H of the gradually expanded portion at predetermined points over a predetermined length L of the gradually expanded portion. The height H is along the radii, while the length L is parallel to the center line X. In an embodiment in accordance with the present disclosure, it was found that the improved clamping capacity results from a gradual expansion angle 22 between approximately 139 ° and approximately 156 ° and an optimal curve 24 represented by the equation interval of y = 16.127x3 - 1.5061x2 + 0.0568x + 0.0001 a and = 6.9136x3 - 0. 5598x2 + 0.0168x + 0.0003, where y is the increasing increase in height H of the curvature in distance x along the length L of the curve. In another embodiment according to the present description, it was found that a gradual expansion angle 22 of approximately 145 ° and an optimal curve 24 represented by the equation y = 11.27x3 - 1.0172x2 + 0.024x + 0.0002, provides maximized holding capacity. In another embodiment according to the present disclosure, it was found that a gradual expansion angle 22 between approximately 130 ° and approximately 147 ° and an optimal curve 24 represented by the equation interval y = 4.8311x3 - 0.1841x2 + 0.086x - 0.0006 a = 3.3937x3 + 0.0994x2 + 0.014x + 0.00004, provides improved clamping capacity. In a further embodiment according to the present disclosure, it was found that a gradual expansion angle 22 of approximately 140 ° and an optimal curve 24 represented by the equation y = 1.7529x3 = 0.7442x2 - 0.0194x + 0.0006, provides holding capacity maximized The tampon applicator 10 with improved finger grip 20 having any of the gradual expansion angles 22 and optimal curves 24 mentioned above was found to unexpectedly provide guidance, comfort and improved placement of a tampon bandage in the vaginal vault over those tampon applicators that do not have the improved and novel features in accordance with the present disclosure. Referring to Figure 3, another tampon applicator with an improved finger grip in accordance with the present disclosure was generally represented by the reference number 30. The applicator 30 is similar to the applicator 10 in Figure 1 and further includes a section of finger grip 32 having one or more clamping structures 34 and optionally a gradually expanded portion 36. The gradually expanded portion 36 may have the same optimal curves of gradually expanded portions mentioned above. It was unexpectedly found through consumer testing that the finger grip section 32 having one or more fastening structures 34 provides improved fastening capacity, which results in improved insertion control. One or more holding structures 34 may be present in any number. In one embodiment according to the present disclosure, one or more clamping structures 34 are present in a number or in an amount between approximately two (2) to approximately six (6). In another embodiment, the finger grip section 32 has five (5) fastening structures 34. In another embodiment, the finger grip section 32 has three (3) grip structures 34. It was unexpectedly determined through extensive investigation that when three grip structures are used in finger grip section 32, they should be spaced approximately 0.444 cm ( 0.175 inches) up to approximately 0.571 cm (0.225 inches) for optimum improvement of clamping capacity. In embodiments where three holding structures are used, it was unexpectedly found that each holding structure has an optimum spacing of approximately 0.5 cm (0.2 inches). It was unexpectedly found that when five clamping structures are used in the finger grip section 32, approximately 0.190 cm (0.075 inches) to approximately 0.317 cm (0.125 inches) should be spaced for optimum improvement of clamping capacity. In embodiments where five holding structures are used, it was unexpectedly found that each holding structure has an optimum spacing of approximately 0.2 cm (0.1 inches). One or more fastening structures 34 may be formed in any design or configuration. Suitable configurations include, but are not limited to, ring, wave ring, discontinuous ring, channels, or any combination thereof. The gradual expansion defined as a gradual expansion outward. The finger grip sections 18 and 32 of Figures 1 and 3, respectively, are defined from the plane along the edge 4 to the free end of the barrel 6. Referring to Figure 4, in one embodiment of the present disclosure the tampon applicator 40 has a finger grip section 42 with one or more corrugated ring fastening structures 44. A novel aspect of one or more corrugated rings 44 is that each ring has an oscillating configuration, similar to a sine or cosine wave. As a result, a multidirectional support is formed. Referring to Fig. 5, which is an exploded view of area B in Fig. 4, in each corrugated ring 44, there is a first fastening portion 46 that provides a user with fastening in the insertion direction, a second portion of fastener 47 that provides a user with restraint in both directions of insertion and removal, and a third fastening portion 48 that provides a wearer with restraint in the direction of removal. To achieve the desired improved fastening characteristics of the present disclosure, one or more corrugated ring fastening structures 44 must have an amplitude between about 0. 02 cm (0.01 inches) to approximately 0. 10 cm (0. 04 inches). The amplitude is defined an M in Figure 6, and is the maximum point of 44 measured at 50. In one embodiment of the present disclosure, one or more corrugated ring fastening structures 44 have an amplitude of approximately 0.063 cm (0.025 inches). One or more corrugated ring fastening structures 44 should have a wavelength between about 0.2 cm (0.1 inches) to about 1.0 cm (0.4 inches). The wavelength is shown as between W to V at 50. In one embodiment of the present disclosure, one or more corrugated ring fastening structures 44 have a wavelength of approximately 0.63 cm (0.25 inches). When referring to Fig. 6, one or more corrugated fastening structures 44 can be oriented "in phase" with respect to the centerline 50, which thereby provides a symmetrical configuration. Referring to Figure 7, one or more corrugated fastening structures 44 may be oriented "out of phase" with respect to the center line 50. While the fastening structures are shown in a particular orientation in Figure 7, it should be understood that can be distributed in any suitable "out of phase" configuration. Referring to Figure 8, a cut away view of the tampon applicator of Figure 4 along the line AA is generally represented by the reference numeral 60. The applicator 60 has a finger grip portion 62 that includes one or more clamping structures corrugated 64. Referring to Figure 8a, an exploded view of one of the corrugated fastening structures 64 in area C of Figure 8 is illustrated. The corrugated clamping structure 64 has a clamping tail 66, which provides clamping in the direction of removal. Referring to Figure 8b, an exploded view of one of the corrugated fastening structures 64 in the area D of Figure 8 is illustrated. The corrugated fastening structure 64 has a fastening tail 68, which provides fastening in the direction of insertion Even in another embodiment of the present disclosure, it was found only that one or more corrugated fastening structures have different fastening characteristics as a result of the molding process. It was found that a tail portion of the retaining structure was formed only during the molding process when the part was ejected from the mole. During ejection, the mold pulls the soft plastic holding structure that creates the tail of the present disclosure. These different clamping characteristics provide additional improved multidirectional clamping capability for the tampon applicator. Referring to Figure 9, the tampon applicator 70 is shown and has a finger grip section 72 with one or more corrugated fastening structures 74. Each Wavy clamping structure 74 oscillates in a shape similar to a sine or cosine wave. Throughout each corrugated fastening structure 74, the fastener alternates in the clamping direction, as illustrated in the exploded views. In the case of tampon applicator 70, at the bottom 76 of the corrugated fastening structure 74 the corrugated fastening structure has a tail 78 which curves towards the removal end of the applicator. This provides improved holding capacity during insertion of the tampon applicator into the vaginal cavity. At half 80 of the corrugated fastening structure 74, the corrugated fastening structure has a straighter tail 82 as it begins to oscillate. This straighter tail 78 can advantageously provide holding capacity in both directions of insertion and removal. In the upper part 84 of the corrugated fastening structure 74, the corrugated fastening structure has a tail 86 which curves towards the insertion end of the applicator 70. This provides improved fastening capacity during the removal of the tampon applicator from the vagina. . EXAMPLES Ultra-class buffer applicators having a finger grip gradually expanded in accordance with the present disclosure with a diameter of objective gradual expansion. The expanded portion was gradually measured, where and is the increasing increase in the height H of the gradual expansion in the distance x along the length of the gradual expansion. The measurements were mentioned later in Table 1. Table 1. Measures of finger grip gradually expanded - Ultra Buffer Gradual Expansion Diameter Target (centimeters) Distance 1.333 1.358 1.397 1.435 1.460 (x axis) Y axis 0.000 0.0000 0.0000 0.0000 0.0000 0.0000 0.063 0.0017 0.0017 0.0010 0.0030 0.0022 0.127 0.0025 0.0027 0.0025 0.0048 0.0038 0.190 0.0025 0.0027 0.0025 0.0093 0.0078 0.254 0.0073 0.0076 0.0088 0.0175 0.0160 0.317 0.0170 0.0175 0.0215 0.0365 0.0373 0.381 0.0363 0.0335 0.0474 0.0718 0.0744 0.444 0.0665 0.0601 0.0899 0.1224 0.1313 0.482 0.1684 0.490 0.1600 0.508 0.1041 0.0949 0.1363 0.525 0.1117 Distance Y axis (x axis) 0.535 0.1092 Angle of 156 ° 149 ° 145 ° 141 ° 139 ° gradual expansion refer to Figure 10, the above measurements were plotted on a graph, which details the curvature of the gradual expansion of each tampon applicator. Additionally, Figure 10 indicates the corresponding equation representing each gradual expansion. Buffers of the Regular class having a finger grip according to the present invention with an objective gradual expansion diameter were formed. The gradually expanded portion was measured, where and is the increasing increase in the height H of the gradual expansion in distance x along the length of the gradual expansion. The measurements were mentioned later in Table 2. Table 2. Measures of finger grip gradually expanded - Regular Bump Gradual Expansion Diameter Target (centimeters) Distance 1,143 1,168 1,220 1,244 1,270 (x axis) Y axis 0. 000 0.0000 0.0000 0.0000 0.0000 0.0000 Distance Y axis (axis x) 0.063 0.0020 0.0078 0.0025 0.0012 0.0035 0.127 0.0033 0.0066 0.0066 0.0035 0.0083 0.190 0.0066 0.0111 0.0116 0.0055 0.0152 0.254 0.0152 0.0203 0.0218 0.0116 0.0269 0.317 0.0259 0.0327 0.0256 0.0254 0.0457 0.381 0.0406 0.0500 0.0528 0.0419 0.0657 0.444 0.0601 0.0721 0.0756 0.0640 0.0899 0.508 0.0866 0.1005 0.1046 0.0939 0.1201 0.571 0.1176 0.1333 0.1394 0.1297 0.1559 0.635 0.1602 0.1750 0.1747 0.1930 0.2207 0.000 0.0000 0.0000 0.0000 0.0000 0.0000 0.063 0.0020 0.0078 0.0025 0.0012 0.0035 Angle 147 ° 145 ° 140 ° 135 ° 130 ° gradual expansion When referring to Figure 11, the previous measurements were plotted on a graph, which details the curvature of the gradual expansion of each tampon applicator. Additionally, Figure 11. indicates the corresponding equation representing each gradual expansion. In one embodiment of the present disclosure, a tampon applicator (Applicator 1) having a finger grip gradually expanded with an expansion angle gradual between approximately 139 ° and approximately 156 ° and an optimal curve represented by the equation interval of y = 16.127x3 - 1.506x2 + 0.0568x + 0.0001 at y = 6.9136x3 -0.5598x2 + 0.0168x + 0.0003 was formed. The tampon applicator also had five corrugated fastening structures, such as those in Figure 9, spaced from each other at approximately 0.190 cm (0.075 inches) to approximately 0.317 cm (0.125 inches). In another embodiment according to the present disclosure, a tampon applicator (Applicator 2) having a finger grip gradually expanded with a gradual expansion angle between about 130 ° and about 137 ° and an optimal curve represented by the equation range and = 4.8311x3 - 0.1841x2 + 0.086x -0.0006 ay = 3.3937x3 + 0.0994x2 + 0.014x + 0.00004 was formed. This tampon applicator also had three ring fastening structures, such as those in Figure 3, spaced from each other at approximately 0.444 cm (0.175 inches) to approximately 0.571 cm (0.225 inches). A blind study (n = 31) was made by comparing tampon applicators in accordance with the present disclosure (Applicator 1 and Applicator 2) with ^ commercially available tampon applicators. The tested tampons were subsequently listed in Table 3 with the corresponding index on a scale of 1 to 8, with 1 being very preferred and 8 being less preferred. Table 3. Study of aplxcador As is evident from the data, tampon applicators in accordance with the present disclosure were clearly preferred over commercially tested products. This is not a surprise since the improved properties imparted to a tampon applicator formed in accordance with the present disclosure result in an applicator having improved restraint during use, resulting in better control and proper placement of a bandage on the vaginal vault. It is made constant that in relation to this date, the best method known by the applicant to carry out said invention is that which is clear from the present description of the invention.

Claims

CLAIMS Having described the invention as above, the content of the following claims is claimed as property: 1. A tampon applicator finger grip, characterized in that it comprises one or more gradually expanded portions having a gradual expansion angle between approximately 139 °. and approximately 156 ° and a curve represented by an equation interval of y 16.127x3 -1.5061x2 + 0.0568x + 0.00010ay = 6.9136x3 - 0.5598x2 + 0.0168x + 0.0003, where y is a growing increase in a height of the curvature at a distance along a length of the curve.
2. - The tampon applicator finger grip according to claim 1, characterized in that the gradual expansion angle is approximately 145 °.
3. - The tampon applicator finger grip according to claim 1, characterized in that the curvature is represented by the equation y = 11.27x3 - 1.0172x2 + 0.024x + 0.0002.
4. - The tampon applicator finger grip according to claim 1, characterized in that it also comprises one or more fastening structures.
5. - The tampon applicator finger grip according to claim 4, characterized in that a or more holding structures have a configuration selected from the group consisting of ring, wavy ring, discontinuous ring, channel, and any combination thereof. 6. - The tampon applicator finger grip according to claim 4, characterized in that one or more clamping structures are present in a number between approximately 2 to approximately
6.
7. - A tampon applicator finger grip, characterized in that comprises one or more gradually expanded portions having a gradual expansion angle between about 130 ° and about 147 ° and a curve represented by an equation interval y = 4.8311x3 -0.1841x2 + 0.086x - 0.0006 a and = 3.3937x3 + 0.0994x2 + 0.014x + 0.00004, where y is an increasing increase in a height of the curvature at a distance along a curve length.
8. - The tampon applicator finger grip according to claim 7, characterized in that the gradual expansion angle is approximately 140 °.
9. - The tampon applicator finger grip according to claim 7, characterized in that the curve is represented by an equation y = 1.7529x3 = 0.7442x2 -0.0194x + 0.0006.
10. - The finger grip of tampon applicator according to claim 7, characterized in that it also comprises one or more clamping structures.
11. - The tampon applicator finger grip according to claim 10, characterized in that one or more fastening structures have a configuration selected from the group consisting of ring, corrugated ring, discontinuous ring, channel, and any combination thereof. the same .
12. - The tampon applicator finger grip according to claim 10, characterized in that one or more clamping structures are present in a number between approximately 2 to approximately 6.
13. - A tampon applicator, characterized in that it comprises: barrel; a finger grip section extending from the barrel having three holding structures, wherein each of the three holding structures is spaced between approximately 0.444 cm (0.175 inches) to approximately 0.571 cm (0.225 inches), where the The finger grip section has a first section of a uniform diameter extending from the barrel and a gradual expansion extending from the first section at one end of the first section opposite the barrel.
14. - The tampon applicator according to claim 13, characterized in that each of the three fastening structures is spaced approximately 0.5 cm (0.2 inches).
15. - The tampon applicator, according to claim 13, characterized in that the three fastening structures have a configuration selected from the group consisting of ring, corrugated ring, discontinuous ring, channel, and any combination thereof.
16. - An applicator / tampon characterized in that it comprises a finger grip section having five fastening structures, wherein each of the five fastening structures is spaced between approximately 0.190 cm (0.075 inches) to approximately 0.317 cm (0.125 inches) ).
17. - The tampon applicator according to claim 16, characterized in that each of the five fastening structures is spaced approximately 0.2 cm (0.1 inches).
18. - The tampon applicator according to claim 16, characterized in that the five fastening structures have a configuration selected from the group consisting of ring, corrugated ring, discontinuous ring, channel, and any combination thereof.
19. - A tampon applicator, characterized in that it comprises a finger grip section having one or more corrugated ring fastening structures similar to the channel with an oscillating configuration.
20. - The tampon applicator according to claim 19, characterized in that one or more corrugated ring fastening structures comprises: a first fastening portion that provides fastening in an insertion direction; a second fastening portion that provides support in both an insertion direction and a removal direction; and a third fastening portion that provides fastening in a removal direction.
21. - The tampon applicator according to claim 19, characterized in that one or more corrugated ring fastening structures have an amplitude between approximately 0.02 cm (0.01 inches) to approximately 0.10 cm (0.04 inches).
22. - The tampon applicator according to claim 19, characterized in that one or more corrugated ring fastening structures have an amplitude of approximately 0.063 cm (0.025 inches).
23. - The tampon applicator according to claim 19, characterized in that one or more corrugated ring fastening structures have a wavelength between about 0.2 cm (0.1 inches) to about 1.01 cm (0.4 inches).
24. - The tampon applicator in accordance with the claim 19, characterized in that one or more corrugated ring fastening structures have a wavelength of approximately 0.63 cm (0.25 inches).
25. - The tampon applicator according to claim 19, characterized in that one or more corrugated fastening structures are oriented in phase, out of phase, or any combination thereof.
26. - The tampon applicator according to claim 20, characterized in that the first fastening portion comprises a first fastening glue that provides fastening in an insertion direction.
27. - The tampon applicator according to claim 26, characterized in that the first succession tail is curved towards a removal end of the tampon applicator.
28. - The tampon applicator according to claim 20, characterized in that the third fastening portion comprises a second fastening glue that provides fastening in a removal direction.
29. - The tampon applicator according to claim 28, characterized in that the second clamping tail is curved towards an insertion end of the tampon applicator.
30.- A tampon applicator, characterized in that it has a finger grip gradually expanded with an angle of gradual expansion between approximately 139 ° approximately 156 ° and a curve represented by an equation interval of y = 16.127x3 - 1.5061x2 + 0.0568c + 0.0001 a and = 6.9136x3 - 0.5598x2 + 0.0168x + 0.0003 where y is an increase increasing at a height of the curve at a distance along a length of the curve, and wherein the expanded finger grip gradually comprises five corrugated fastening structures spaced apart from each other at approximately 0.190 cm (0.075 inches) to approximately 0.317 cm (0.125 inches).
31.- A tampon applicator, characterized in that it has a finger grip gradually expanded with a gradual expansion angle between approximately 130 ° of approximately 147 ° and a curve represented by a range of equation y = 4.8311x3 - 0.1841x2 + 0.086x - 0.0006 a and = 3.3937x3 + 0.0994x2 + 0.014x + 0.00004 where y is a growing increase in a height of the curve over a distance along a curve length, and where the expanded finger grip gradually comprises three structures ring fasteners spaced apart at approximately 0.444 cm (0.175 inches) to approximately 0.571 cm (0.225 inches).